1. The Field of the Invention
The present invention relates to quick release apparatuses and methods. Specifically, the present invention relates to quick release apparatuses and methods for installing and removing optical elements.
2. The Relevant Technology
High-content screening (“HCS”) is a cell-based screening method that yields detailed information about the temporal-spatial dynamics of cell constituents and processes, and plays an important role in the use of cell-based screening for identification and validation of drug candidates. The information provided by HCS alleviates bottlenecks in the drug discovery process by providing deep biological information. The assays associated with this method use either fixed or live cells, depending on the biological information desired.
In one method of performing an HCS scan, the cells of interest are loaded into an array of wells in a standard specimen plate (also known as a titer or microtiter plate). The specimen plate is then positioned in a plate holder on a stage within an imaging system so that the specimen plate can move horizontally with the stage. The imaging system also includes a microscope. Motors are attached to the stage so that the stage and the specimen plate can be moved with respect to the microscope in both directions orthogonal to the microscope. As a result, any of the individual wells can be positioned in alignment with the microscope so as to be able to be imaged through the microscope objective.
The image obtained through the objective can be recorded using a camera system, such as, e.g., a Charge-Coupled Device (CCD) camera system. A wide variety of auxiliary components, such as electromechanical shutters and axial focus control mechanisms can be used to aid in obtaining and recording the images through the microscope. These components are typically interactively controlled by a computer using proprietary or commercially available image acquisition software.
Another useful component for automatic multi-color fluorescence imaging is a device for rapidly switching between different wavelengths of light. In a conventional configuration, a fluorescence filter set is housed in an optical block and contains an excitation filter and a barrier (or emission) filter, as well as a dichromatic mirror that directs excitation light to the specimen and transmits emission light to a detector in the camera system. For live-cell imaging using more advanced filter technology, the dichromatic mirror can be retained, but is often substituted for a polychromatic derivative that contains multiple bandpass regions. The excitation and emission filters can be removed from the optical block and placed in filter changers that can include a plurality of filter elements.
There are several practical mechanisms for automatically interchanging fluorescence filters. The most common involves rotating thin filter wheels having a number of filter elements mounted thereon. Filter wheels are reliable, relatively inexpensive, and supported by a large number of aftermarket and proprietary image acquisition programs. Among the major benefits of filter wheels are their high light transmission efficiency and the flexibility to use a wide range of commercially available filters.
One of the disadvantages of filter wheels is their limitation in switching speed. That is, it takes a finite amount of time to move between filter elements on the filter wheel. This can cause a significant delay to build up when imaging many cells, as is often done in HCS scans. To help mitigate this limitation, conventional filter wheels are thin and light and only accommodate up to about ten filter elements at a time. Although this helps mitigate the speed issue, it also causes other problems. For example, filter wheels must be manually changed out every time a filter element is desired that is not mounted on the filter wheel being used. This takes significantly more time than the delay caused by moving between filter elements on the filter wheel and thus greatly exacerbates the speed delay problems. Because only a few filter elements are mounted on a filter wheel, the changing out of filters wheels can occur often, especially due to the nature of fluoroscopy.
In some conventional configurations, the filter elements themselves are changed out instead of the filter wheel. To accommodate this, each filter element can be part of a filter that is threaded into an aperture formed on the filter wheel. Conventional filters include housings, adapters and retaining rings. A lens or filter element is placed inside the housing, which is usually circular, then held fast with an internal retaining ring. This sandwich of components, in turn, threads into the aperture on the filter wheel, often using an adapter to match the threading on the aperture. Because of the thinness of the filter wheel and the filter assembly, the threads are very thin and precise. As a result, a series of precise and costly threaded components are required on the filter components, along with special tools to change out the filters. In addition, the small size of the threads requires a dexterity on the part of the user, and special care must be taken during installation to not damage the components or the threads.